JP2001255188A - Flow rate and flowing velocity measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flow rate and flowing velocity measuring apparatus, capable of accurately measuring a flowing velocity and a flow rate of the flow forward for a long period by preventing contamination of a detection element by a contaminant to be conveyed by a back flow. SOLUTION: The flow rate and flowing velocity measuring apparatus comprises a main flow tube, in which a fluid to be measured flows in the forward direction (a direction Mf) or a backward direction (a direction Mc), a distributing tube 2 having a distributing passage 3 connected to the main flow tube and introduced with the fluid to be measured, and the detecting element 7 exposed with the fluid flow in the passage 3. In this case, the passage 3 has a throttle R, formed at an upstream side of the element 6, inflection parts 3a, 3b provided between the element 7 and an outlet 5 to inflect an fluid flow introduced, a retention space 8 for retaining the back flow introduced reversely from the outlet 5 at an outer peripheral side of the part 3b, directly in front of the outlet 5, and a channel wall surface inclined toward a direction to become the downstream side, when the fluid flows in the forward direction (direction Mf) from the upstream side toward the outlet 5 near the outlet 5. In this case, an angle θ, formed between a direction DF of the fluid flow guided from the outlet 5 and the flowing direction of the forward flow Mf, is an acute angle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for measuring various quantities relating to flow, in particular flow and flow velocity, and more particularly to a temperature-dependent detection element and / or a detection element integrally formed on a semiconductor chip. For example, a mass flow sensor for controlling combustion of a vehicle or an industrial engine, or a mass flow sensor for an industrial air conditioning system or a compressor air supply system, and also for controlling the air-fuel ratio of a household gas stove. The present invention relates to a measurement device suitably applied as a flow sensor or the like.

[0002]

2. Description of the Related Art In recent years, in the situation surrounding automobiles (especially four-wheeled vehicles), environmental considerations such as emission regulations have been given the most importance. In order to comply with these regulations, more precise engine combustion control is required. Therefore, various proposals have been made regarding the flow path structure of the engine combustion control mass sensor. For example, JP-A-8-271293 and JP-A-11-14421 have a structure in which a shunt tube is connected to an intake pipe of an engine to take in the measurement fluid, and a flow rate is measured in the shunt tube. There has been proposed a measuring device which is hardly affected by pulsation of an engine and realizes high-precision flow measurement.

[0003]

According to the knowledge of the present inventors, regarding the improvement of the accuracy of a mass flow sensor for controlling the combustion of an engine for an automobile, the influence of the backflow and the pulsation on the measurement of the intake air amount is also a problem. Further, the backflow of contaminants from the engine due to the backflow damages the detection element, which is also a serious problem. Note that "backflow" refers to a flow flowing from the engine to the intake port in the intake pipe, while "forward flow" refers to a normal flow flowing from the intake port to the engine in the intake pipe, i.e., suction. Refers to the flow of air.

However, the above-mentioned Japanese Patent Application Laid-Open Nos. 8-271293 and 11-14421 do not mention the contamination resistance of the detecting element against backflow or the deterioration of detection accuracy due to contamination.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a flow rate and flow velocity measuring apparatus which can prevent the detection element from being contaminated by contaminants conveyed by a back flow and can measure the forward flow velocity and the flow rate with high accuracy over a long period of time. It is.

[0006]

According to a first aspect of the present invention, there is provided a branch channel into which a flow to be measured is introduced, and a flow-related quantity, particularly a flow rate and a flow rate, which are exposed to the flow in the branch channel. And a detection element that is provided between the detection element and the outlet of the branch flow path in the middle of the branch flow path and that retains at least a part of the backflow reversely introduced from the discharge opening. And a space, and in the vicinity of the outlet of the branch flow path, when the flow to be measured flows in the forward direction (in the pipe to be measured or in the main flow pipe), the branch flow path is directed to the downstream side toward the outlet. A measuring device is provided for a flow that is inclined toward one end.

According to this measuring device, the influence of the backflow on the measurement accuracy is reduced and the influence of the pulsation is also reduced by providing the stagnation space in the middle of the branch channel. That is, a surge function is exhibited. At the same time, a large number of contaminants contained in the backflow are prevented from reaching the detection element, and contamination of the detection element is prevented. That is, a trap function is exhibited. As a result, the influence of the backflow and further the pulsation on the measurement in the forward flow direction is suppressed, and various quantities relating to the forward flow can be detected with high accuracy over a long period of time. In addition, since the residence space is arranged downstream of the detection element, responsiveness when measuring various quantities related to the forward flow is improved.

[0008] Further, the branch flow path is inclined in the vicinity of the outlet toward the downstream side of the flow to be measured. As a result, the direction of the flow derived from the outlet and the flow direction of the flow to be measured in the forward direction are formed. By making the angle acute, pressure loss and measurement error are reduced. Hereinafter, the reason why these effects are provided will be described.

[Reduction of Pressure Loss] The flow path near the outlet of the branch flow path is assumed to be such that the flow derived from the branch flow outlet is derived in a direction perpendicular to the main flow direction of the flow to be measured. If it is formed, a vortex is surely generated at the junction of the derived flow and the flow to be measured, that is, in the vicinity of the outlet and outside the branch pipe, and the pressure loss of the measured flow increases. Therefore,
As in the present invention, the derivation direction of the flow from the outlet is directed toward the downstream side when the flow to be measured flowing in the forward direction flows in the forward direction, and the derivation direction is relative to the forward direction of the flow to be measured. By making the angle as sharp as possible, this pressure loss is reduced.

[Reduction of Measurement Error] Similarly, if the flow derived from the outlet of the branch flow is derived in a direction orthogonal to the main flow direction of the flow to be measured, the flow near the outlet of the branch flow is assumed. When the flow path is formed, if the flow to be measured flows in the opposite direction, the flow to be measured cannot enter the branch pipe at all. Pull it out. As a result, the detection element erroneously detects the forward flow despite the occurrence of the backward flow, and the measurement error increases dramatically. Therefore, as in the present invention, when the flow to be measured flows in the reverse direction by directing the flow direction of the flow from the outlet to the downstream side when the flow to be measured flows in the forward direction. Is ensured that the flow to be measured is introduced from the outlet and is derived from the inlet. Thereby, measurement errors due to the above-described causes are reduced.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described.

According to a preferred embodiment of the present invention, the inlet of the branch channel is opened so as to be orthogonal to the flow to be measured, and the outlet is opened essentially parallel to the flow to be measured. The detection element is provided in the vicinity of the downstream of the inlet, and has a structure in which the flow is narrowed down from the inlet to the vicinity of the downstream of the detection element. by this,
The speed of the flow from the inlet to the detection element is improved, and the responsiveness of the measurement is improved. Further, by the structure in which the fluid is constricted, separation of the flow to be measured on the surface of the detection element is suppressed, and a high-precision output with respect to the forward flow is obtained in the entire flow rate region.

In a preferred embodiment of the present invention,
In the structure in which the flow is narrowed, a portion where the cross-sectional area of the flow passage is rapidly increased is provided immediately downstream of the portion where the cross-sectional area of the flow passage is narrowest, and a plurality of inflection portions are provided in the branch flow passage to increase the total length of the branch flow passage Then, a stay space is provided near the inflection portion near the outlet. With this structure, when backflow and pulsation occur, their effects can be canceled before reaching the detection element, and a high-precision output can be obtained for the measurement of the flow rate and the flow velocity of the forward flow.

In a preferred embodiment of the present invention,
In the vicinity of the outlet of the shunt channel, the shunt channel is directed toward the outlet, or the channel from the stagnation space of the shunt channel to the outlet is downstream when the flow to be measured flows in the forward direction. Inclined toward. Thereby, the angle between the direction of the flow led out into the flow to be measured through the outlet and the basic flow direction when the flow to be measured flows in the forward direction is an acute angle.

In a preferred embodiment of the present invention, the stay space is a space where the backflow from the outlet is reversed. In addition, the retention space is formed at the end of the flow path (reverse flow path) or at the next inflection part (in the case of a forward flow, the inflection part reaching the next outlet, that is, the inflection part at the subsequent stage). Is preferably performed. As shown in FIG. 2B described later, it is particularly preferable that the stay space is formed as a region (shown by cross-hatching) where the backflow from the outlet directly hits and stays.

In a preferred embodiment of the present invention,
A stay space is provided immediately before (in the vicinity or upstream of) the outlet. Also, preferably, the stay space is provided so as to be closer to the upstream side when the flow to be measured flows in the forward direction immediately before the outlet.

In a preferred embodiment of the present invention,
An inflection portion for inflection or reversal of the flow is provided in the branch flow path, and the stay space is provided immediately before the outlet and on the outer peripheral side of the inflection portion.

In a preferred embodiment of the present invention, the stay space includes a concave portion in which the flow path wall of the branch flow path is retreated.

In a preferred embodiment of the present invention,
A sub-residence space that communicates with the retention space and stores the contaminants contained in the backflow is provided.

In a preferred embodiment of the present invention,
In the flow path wall surrounding the outlet of the branch flow path, when the flow to be measured flows in the forward direction, the flow path wall on the downstream side protrudes into the flow to be measured more than the flow path wall on the upstream side. I have.

In a preferred embodiment of the present invention,
In the branch channel, a throttle is formed on the upstream side of the detection element, and a portion of the throttle with the smallest channel cross-sectional diameter is formed on the detection element. In other words, the narrowest part of the fluid restrictor mechanism in which the cross-sectional area of the shunt channel gradually decreases is disposed to face the detection surface of the detection element, and the narrowest part is at least inside the detection element relative to the downstream end of the detection element. It is in. Thereby, separation of the flow to be measured on the detection element (detection surface) is prevented, and higher precision measurement is possible. In addition, the restriction reduces the influence of the pulsation of the measured flow (pulsation of the internal combustion engine) on the measurement. Preferably, the flow path cross-sectional area of the branch flow path is abruptly increased downstream of the portion having the smallest flow path cross-sectional diameter. This further reduces the effects of backflow and pulsation on forward flow measurements.

In a preferred embodiment of the present invention,
The following detection element is used. That is, this detection element is basically a semiconductor chip provided with four thin film resistors. More specifically, a diaphragm portion and a rim portion are provided on the semiconductor layer. The diaphragm section has (1) an upstream temperature sensor and (2) a downstream temperature sensor,
(3) A heater is provided between the upstream temperature sensor. On the other hand, the rim is provided with (4) an ambient temperature sensor. The diaphragm is made extremely thin to achieve thermal insulation.

Next, the principle of detecting various quantities relating to the flow such as the flow velocity and the flow rate using the detection element will be described below. (1) The power supplied to the heater is controlled so that the heater always has a constant temperature difference with respect to the ambient temperature. (2) Therefore, when there is no flow, the temperatures of the upstream temperature sensor and the downstream temperature sensor are substantially equal. (3) However, if there is a flow, the temperature of the upstream temperature sensor decreases because heat escapes from its surface. The temperature change of the downstream temperature sensor is smaller than that of the upstream temperature sensor because the heat input from the heater increases. Note that the temperature of the downstream temperature sensor may increase. (4) The flow rate, the flow velocity, and the like are detected based on the temperature difference between the upstream temperature sensor and the downstream temperature sensor, and the flow direction is detected from the sign of the temperature difference. The temperature difference can be detected based on a change in electric resistance due to temperature.

In a preferred embodiment of the present invention,
The sensing element measures a flow-related quantity including at least a flow rate and / or a flow rate based on the temperature.

In a preferred embodiment of the present invention, the measuring device according to the present invention is installed in an intake system of an engine of various vehicles, and is applied to measurement of an intake air amount of an engine mounted on a two-wheel or four-wheel vehicle. can do. For example, the measuring device according to the present invention is installed between an air cleaner and a throttle valve in an intake system of an engine mounted on a four-wheeled vehicle. Further, the measuring device according to the present invention is attached to a two-wheeled vehicle intake pipe (air funnel) connected to a cylinder in an intake system of an engine mounted on a two-wheeled vehicle in order to measure a flow rate or a flow speed of intake air.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to further clarify the preferred embodiments of the present invention described above, an embodiment of the present invention will be described below with reference to the drawings.

[Embodiment 1] A flow and flow velocity measuring apparatus according to Embodiment 1 of the present invention will be described. 1 (A) to 1 (C)
FIG. 1A is an explanatory view of this measuring device, in which FIG. 1A is a cross-sectional view cut along the flow direction of a main flow (measured flow), and FIG. BB sectional view, FIG.
FIG. 2C is a sectional view taken along line CC in FIG. In addition,
When the main flow is flowing in the direction shown in FIG. 1A, this flow is called “forward flow Mf”, and when the main flow is flowing in the opposite direction, this flow is called “backflow Mc” (FIG. 2). (A)).

Referring to FIG. 1A, the main flow which is the flow to be measured, in particular, a part of the flow of the forward flow Mf can be introduced.
The housing of the branch pipe 2 is attached to the housing (not shown) of the main flow pipe. In the branch pipe 2, a bent branch channel 3 is formed. The inlet 4 of the branch channel 3 is largely open on a plane substantially perpendicular to the flow direction of the main flow or the forward flow Mf. The outlet 5 of the branch channel 3 has a main flow or a forward flow Mf.
Are opened in a plane substantially parallel to the flow direction.

The flow path wall surrounding the outlet 5 is inclined with respect to the illustrated main flow or the basic flow direction of the forward flow Mf. Specifically, in the vicinity of the outlet 5, the branch flow path 3 is downstream when the main flow flows in the forward direction as shown in the drawing from the upstream side toward the outlet 5, that is, when the forward flow Mf flows. It is inclined toward. Thereby, the angle θ between the direction DF of the flow led out into the main flow (flow to be measured) through the outlet 5 and the basic flow direction of the forward flow Mf (axial direction of the main flow pipe) is an acute angle. .

In particular, referring to FIG.
, Upstream of the position where the detection element 7 is arranged,
A stop R is formed in which the flow cross-sectional diameter of the branch channel 3 is gradually reduced from the inlet 4 side toward the detection element 7 side. In the throttle R, a portion N where the flow cross section diameter is the smallest is located on the detection element 7. Then, the flow cross section diameter of the branch flow path 3 is rapidly increased toward the downstream from the portion N where the flow cross section diameter is the smallest.

In particular, referring to FIG.
, A substrate 6 constituting a part of the flow path wall of the branch flow path 3 is detachably attached. The detection element 7 is supported on the substrate 6 so as to be exposed to the flow in the branch channel 3. The substrate 6 supporting the detection element 7 can be mounted and replaced from outside the mainstream pipe (not shown).

Referring again to FIG. 1A, the branch flow path 3
The first and second inflection portions 3a and 3b are formed between the detection element 7 and the outlet 5 in order to reverse or largely invert the introduced flow. Further, a stay space 8 is formed downstream of the first inflection portion 3a and on the outer peripheral side of the second inflection portion 3b. The retention space 8 is located immediately before the outlet 5, and more specifically, is located on an extension of the branch channel 3 near the outlet 5 in the pipe axis direction (central axis direction). The backflow introduced from is formed in a portion that goes straight.

Next, the operation of the measuring apparatus when the main flow, which is the flow to be measured, flows in the reverse direction, that is, when the reverse flow occurs, will be described. When the measuring device is mounted on the intake pipe of the internal combustion engine, when a reverse flow, that is, a flow that flows from the cylinder of the internal combustion engine toward the intake port occurs, a forward flow (from the intake port to the cylinder) occurs during the reverse flow. Of the particulate matter (contaminant) PM as compared with the flow (flow toward).

FIG. 2A is an operation diagram of the measuring apparatus shown in FIGS. 1A to 1C, and FIG.
It is an enlarged view near the outlet shown in (A). FIG. 2 (A)
2B, a solid arrow indicates a trajectory of the particulate matter PM, and a broken arrow indicates a gas flow. FIG.
Referring to (A), when the backflow Mc occurs in the mainstream pipe, a part of the particulate matter PM transported by the backflow Mc passes through the outlet 5 in an oblique direction with respect to the opening surface of the inlet 5. It further penetrates into the branch channel 3. Since the inertia of the particulate matter PM is generally large, the particulate matter PM cannot sufficiently follow the inflection of the flow in the second inflection portion 3b, and goes straight as it is, and stays just before the outlet 5. Stay in the space 8. That is, the retaining space 8 exhibits a function of trapping the particulate matter PM. Here, FIG. 2 (B) shows a state in which the particulate matter PM stays in the stay space 8 by cross-hatching. Thus, the particulate matter PM is detected by the detection element 7.
Is prevented from reaching.

Further, the staying space 8 also exhibits a surge function of reducing the speed of the backflow Mc entering the branch channel 3 and delaying the arrival of the backflow Mc on the detecting element 7. Thereby, the flow of the backflow Mc is changed to the forward flow Mf (see FIG. 1A).
The effect on the flow measurement is reduced.

[Second Embodiment] Next, a flow rate and flow velocity measuring apparatus according to a second embodiment of the present invention will be described. The measuring device according to the second embodiment is a modified example of the measuring device according to the first embodiment, and the description of the first embodiment is appropriately referred to in that both measuring devices have the same configuration. In the following description of the second embodiment, mainly the differences between the two will be described.

FIG. 3 is an explanatory view of a flow rate and flow velocity measuring device according to a second embodiment of the present invention, and is a cross-sectional view cut along a main flow direction. Referring to FIG. 3, in the flow path wall surrounding the outlet 5 of the branch flow path 3, the flow path wall face 5 b on the downstream side with respect to the forward flow Mf has a protrusion width T larger than the upstream flow path wall face 5 a. , Protruding into the main stream, that is, the flow to be measured. By this protruding channel wall surface 5b,
Intrusion of the particulate matter PM (see FIG. 2A) conveyed by the backflow is further prevented.

Third Embodiment Next, a flow rate and flow velocity measuring device according to a third embodiment of the present invention will be described. It should be noted that the description of the first embodiment is appropriately referred to in that the third embodiment has the same configuration as the measuring apparatus according to the first embodiment, and in the following description of the third embodiment, both of them are mainly described. The difference will be described.

FIG. 4A is an explanatory view of a flow rate and flow velocity measuring device according to Embodiment 3 of the present invention, and is a cross-sectional view cut along the main flow direction. FIG. 4B is an enlarged view of the vicinity of the outlet shown in FIG.

Referring to FIG. 4A, a bent distribution channel 13 is formed in the distribution tube 12. Dividing channel 13
The inlet 14 of FIG. 1 is greatly expanded and opened on a plane substantially orthogonal to the flow direction of the forward flow Mf. Outlet 15 of branch channel 13
Are opened in a plane substantially parallel to the flow direction of the forward flow Mf.
The flow path wall surrounding the outlet 15 is inclined with respect to the flow direction of the forward flow Mf. Specifically, in the vicinity of the outlet 15, the branch channel 13 is inclined toward the downstream side with respect to the forward flow Mf from the upstream side toward the outlet 15.

The substrate 6 constituting a part of the flow path wall of the flow path 13 is detachably attached to the flow dividing pipe 12. The detection element 7 is supported on the substrate 6 so as to be exposed to the flow in the branch channel 13. In the branch 13, an aperture R whose diameter is reduced toward the detection element 7 is formed upstream of the detection element 7, and a portion where the cross-sectional area of the flow path is rapidly increased is formed downstream of the detection element 7. ing.

In the middle of the branch channel 13, the detecting element 7 and the outlet 1
Between 5, there are formed first and second inflection portions 13a and 13b for reversing or largely inflection of the introduced flow. Further, a stagnation space 18 is formed downstream of the first inflection portion 13 a and on the outer peripheral side of the second inflection portion 13 b and immediately before the outlet 15. This stay space 1
Reference numeral 8 is disposed at a portion where the backflow Mc that has entered from the outlet 15 is substantially straight forward. The retention space 18 has a concave portion 18a (see FIG. 4B) in which the flow path wall of the branch flow path 13 is retracted.

In particular, referring to FIG. 4B, according to this measuring device, when the backflow Mc occurs, the particulate matter PM transported by the backflow Mc moves with respect to the opening surface of the outlet 15. It invades obliquely and is effectively trapped in the retaining space 18, especially the concave portion 18a. Further, the stay space 18 exhibits the surge function for the backflow Mc.

[Fourth Embodiment] Next, a flow rate and flow velocity measuring apparatus according to a fourth embodiment of the present invention will be described. It should be noted that the description of the first embodiment is appropriately referred to in that the fourth embodiment has the same configuration as that of the measuring apparatus according to the first embodiment, and in the following description of the fourth embodiment, both of them are mainly described. The difference will be described.

FIG. 5 is an explanatory view of a flow rate and flow velocity measuring apparatus according to a fourth embodiment of the present invention, and is a cross-sectional view cut along the main flow direction. Referring to FIG. 5, a bent distribution channel 23 is formed in the distribution tube 22.
The introduction port 24 of the branch channel 23 is greatly expanded and opened on a plane substantially perpendicular to the flow direction of the main flow M. The outlet 25 of the branch channel 23 is opened in a plane substantially parallel to the flow direction of the forward flow Mf. The flow channel wall surrounding the outlet 25 is inclined with respect to the basic flow direction of the main flow or the flow direction of the forward flow Mf. Specifically, in the vicinity of the outlet 25, the branch channel 2
3 is a forward flow Mf from the upstream side toward the outlet 25.
With respect to the downstream side.

The substrate 6 forming a part of the flow path wall of the flow distribution path 23 is detachably attached to the flow distribution pipe 22. The detection element 7 is supported on the substrate 6 so as to be exposed to the flow in the branch channel 23. In the branch channel 23, an aperture R whose diameter is reduced toward the detection element 7 is formed upstream of the detection element 7, and a portion where the cross-sectional area of the channel is rapidly increased is formed downstream of the detection element 7. ing.

In the middle of the branch channel 23, the detecting element 7 and the outlet 2
Between 5, there is formed a first inflection portion 23a for largely inflection of the introduced flow. Further, downstream of the first inflection portion 23a and immediately before the outlet 25,
A stagnation space 28 is formed so as to be closer to the upstream side with respect to the forward flow Mf. This stagnation space 28 is arranged in a portion where the backflow that has entered from the outlet 25 is substantially straight forward.

In this measuring device, the particulate matter PM, which has been conveyed on the backflow Mc as in the measuring device shown in FIG. Can be trapped. Further, the stay space 28 exhibits the surge function for the backflow Mc.

[Fifth Embodiment] Next, a flow rate and flow velocity measuring apparatus according to a fifth embodiment of the present invention will be described. It should be noted that the description of the first embodiment is appropriately referred to in regard to the point that the fifth embodiment has the same configuration as the measuring apparatus according to the first embodiment. The difference will be described.

FIG. 6A is an explanatory view of a flow rate and flow velocity measuring apparatus according to Embodiment 5 of the present invention, and is a cross-sectional view cut along the main flow direction. FIG. 6B is an enlarged view of the vicinity of the outlet shown in FIG.

Referring to FIG. 6A, a bent distribution channel 33 is formed in the distribution tube 32. Dividing channel 33
The inlet 34 is largely open at a plane substantially perpendicular to the flow direction of the forward flow Mf. Outlet 35 of branch channel 33
Are opened in a plane substantially parallel to the flow direction of the forward flow Mf.
The channel wall surrounding the outlet 35 is inclined with respect to the forward flow Mf. Specifically, in the vicinity of the outlet 35, the branch channel 33 is inclined toward the downstream side with respect to the forward flow Mf from the upstream side toward the outlet 35.

The substrate 6 constituting a part of the flow path wall of the flow path 33 is detachably attached to the flow dividing pipe 32. The detection element 7 is supported on the substrate 6 so as to be exposed to the flow in the branch channel 33. In the branch flow path 33, an aperture R whose diameter is reduced toward the detection element 7 is formed upstream of the detection element 7, and a portion where the cross-sectional area of the flow path is rapidly increased is formed downstream of the detection element 7. ing.

In the middle of the branch channel 33, the detecting element 7 and the outlet 3
Between 5, there are formed first and second inflection portions 33a and 33b for greatly inflection of the introduced flow. Further, a stagnation space 38 is formed downstream of the first inflection portion 33 a and on the outer peripheral side of the second inflection portion 33 b and near the outlet 35. The stay space 38 performs the trap function and the surge function.

Further, the residence space 3
8, a branch pipe communicating with the branch pipe 33 is formed,
A sub-residence space 39 is formed in the branch pipe.

In particular, referring to FIG. 6B, according to this measuring device, when the backflow Mc occurs, the particulate matter PM conveyed by the backflow Mc moves with respect to the opening surface of the outlet 35. It enters obliquely and is first trapped in the stay space 38. The particulate matter PM whose velocity has been reduced by being trapped eventually falls into the sub-retention space 39 and is stored.

[0056]

The main effects of the present invention are as follows. (1) Contamination of the detection element caused by the backflow is suppressed. (2) The influence of the backflow and the pulsation on the detecting element is reduced. (3) High-precision measurement of various quantities related to the forward flow is possible. (4) Responsiveness in measuring various quantities related to the forward flow is maintained.

[Brief description of the drawings]

1 (A) to 1 (C) are explanatory views of a flow rate and flow velocity measuring device according to a first embodiment of the present invention, wherein (A) is cut along a flow direction of a main flow (measured flow). (B) is a cross-sectional view taken along line BB in (A), and (C) is a cross-sectional view taken along line CC in (A).

2 (A) is an operation diagram of the measuring device shown in FIG. 1 (A), and FIG. 2 (B) is an enlarged view of the vicinity of the outlet shown in FIG. 1 (A).

FIG. 3 is an explanatory diagram of a flow rate and flow velocity measuring device according to a second embodiment of the present invention, and is a cross-sectional view cut along a main flow direction.

FIG. 4A is an explanatory view of a flow rate and flow velocity measuring device according to a third embodiment of the present invention, and is a cross-sectional view cut along a main flow direction. (B) is an enlarged view near the outlet shown in (A).

FIG. 5 is an explanatory diagram of a flow rate and flow velocity measuring device according to a fourth embodiment of the present invention, and is a cross-sectional view cut along a main flow direction.

FIG. 6A is an explanatory view of a flow rate and flow velocity measuring device according to a fifth embodiment of the present invention, and is a cross-sectional view cut along a main flow direction. (B) is an enlarged view near the outlet shown in (A).

[Explanation of symbols]

2 Dividing pipe 3 Dividing channel 3a First inflection portion 3b Second inflection portion 4 Inlet of dividing channel 5 Outlet of dividing channel 5a Upstream channel wall surrounding the exit 5b Downstream flow surrounding the exit Road wall 6 Substrate 7 Detecting element 8 Retention space 12 Dividing tube 13 Dividing channel 13a First inflection section 13b Second inflection section 14 Introducing port of subchannel 15 Deriving port of subchannel 18 Retaining space 18a Depression 22 Dividing pipe 23 branch channel 23a first inflection section 24 branch channel inlet port 25 branch channel outlet 28 residence space 32 branch pipe 33 branch channel 33a first inflection section 33b second inflection section 34 introduction of branch channel Port 35 Outlet of branch channel 38 Reservation space 39 Sub-residence space DF Direction of flow led out into flow to be measured (main flow) through discharge port Mf Forward flow (main flow or flow to be measured flowing forward) Mc Reverse flow (reverse direction) Mainstream flowing to Stone to be measured flows) N iris narrowest portion PM particulate matter (pollutants) R throttle T protruding length

Continued on the front page (72) Inventor Takio Kojima 14-18 Takatsuji-cho, Mizuho-ku, Nagoya-shi Inside Japan Special Ceramics Co., Ltd. (72) Inventor: Masanori Suda, 14-18, Takatsuji-cho, Mizuho-ku, Nagoya-shi, Japan Inside (72) Inventor Takafumi Oshima 14-18, Takatsuji-cho, Mizuho-ku, Nagoya-shi, Japan F-term ( Reference) 2F030 CA10 CC13 CC14 CC15 CD02 CE12 CF09 2F035 AA02 EA08

Claims (15)

[Claims] 1. A dividing channel into which a flow to be measured is introduced, a detecting element exposed to a flow in the dividing channel and detecting various quantities related to a flow such as a flow velocity and a flow rate; A stagnation space provided between the detection element and the outlet of the shunt channel, and stagnates at least a part of the backflow reversely introduced from the outlet, and the shunt channel near the outlet. The flow rate and flow velocity measuring device, characterized in that, as the measured flow flows in the forward direction, it is inclined toward the downstream side as it goes toward the outlet. 2. The flow rate and flow velocity measuring device according to claim 1, further comprising a sub-retention space communicating with the retention space and storing contaminants contained in the backflow. 3. The flow rate and flow velocity measuring device according to claim 1, wherein the staying space is provided immediately before the outlet. 4. An inflection portion for inflection or reversal of a flow is provided in the branch channel, and the staying space is provided immediately before the outlet and on an outer peripheral side of the inflection portion. The flow rate and flow velocity measuring device according to claim 1, characterized in that: 5. The flow rate and the flow velocity according to claim 1, wherein a plurality of inflection portions for inflection or inversion of flow are provided between the detection element and the outlet in the branch flow path. measuring device. 6. The flow rate and flow velocity measuring apparatus according to claim 1, wherein the staying space includes a concave portion in which a flow path wall of the branch flow path is retreated. 7. The flow rate according to claim 1, wherein the stagnation space is formed immediately upstream of the outlet when the flow to be measured flows in a forward direction. And a flow velocity measuring device. 8. The flow path wall surrounding the outlet of the branch flow path, the downstream flow path wall when the flow to be measured flows in the forward direction is measured more than the upstream flow path wall. The flow rate and flow velocity measurement device according to claim 1, wherein the flow rate and flow velocity measurement device protrudes into the flow. 9. An introduction port of the branch flow path is opened on a plane orthogonal to a basic flow direction of the flow to be measured. The flow velocity measuring device according to claim 1, wherein the flow opening is opened in a parallel plane. 10. A substrate that supports the detection element and forms a part of a flow path wall of the branch flow path, wherein the detection element detects a flow on a flow path wall surface of the flow branch path. The flow rate and flow velocity measuring device according to claim 1, wherein: 11. A method according to claim 11, wherein a throttle is formed upstream of the detection element in the branch flow path, and a portion of the throttle having the smallest flow path cross-sectional diameter is formed on the detection element. Item 2. The flow rate and flow velocity measuring device according to Item 1. 12. The flow rate and flow velocity measuring device according to claim 11, wherein a flow path cross-sectional area of the branch flow path is sharply expanded downstream of a position of the flow path having the smallest diameter in the restrictor. . 13. A dividing channel into which a flow to be measured is introduced, a detection element exposed to a flow in the dividing channel, and detecting various quantities related to a flow such as a flow velocity and a flow rate. A stagnant space provided between the detection element and the outlet of the branch channel, and stagnating at least a part of the backflow introduced reversely from the outlet, and the flow to be measured flows in the forward direction. From the stagnant space of the shunt channel to the outlet such that the angle between the basic flow direction in the case of the flow and the direction of the flow led into the flow to be measured through the outlet is an acute angle. A flow rate and flow velocity measuring device, wherein a flow path is formed. 14. A main flow pipe through which a flow to be measured flows in a forward direction or a reverse direction; a diversion pipe connected to the main flow pipe and including a diversion path into which the flow to be measured is introduced; A detecting element for detecting various quantities related to the flow such as a flow velocity and a flow rate, wherein the shunting flow path is formed with a restrictor formed upstream of the detecting element, and formed immediately after the restrictor. A portion having an increased road cross-sectional area; and at least one inflection portion provided between the detection element and the outlet of the branch flow passage, wherein the flow introduced into the branch flow passage is bent. A stagnation space which is provided downstream of the section and is located immediately before the outlet and stagnates at least a part of the backflow introduced reversely from the outlet, and in the vicinity of the outlet of the branch channel, toward the outlet. Therefore, if the flow to be measured flows in the forward direction, The inclined flow paths wall to approach towards that, further comprising a flow rate and flow rate measuring device according to claim. 15. The flow rate and flow velocity measuring device according to claim 14, wherein the inflection portion is a reversal inflection portion for reversing a flow.